Do you wanna mean that your site works both www and non-www ?
I have the same problem on one of my sites.
The site naturally redirects any request without “www” to urls with “WWW” …. all site code has domain urls indicated with “WWW”
When active W. Fastest Cache, the entire code automatically displays the URLs of the domain SIN “www”

Hi @expresaweb, actually WPFC adds a redirection rule which redirects without “www” to urls with “WWW”. Please contact me via email: http://www.wpfastestcache.com/contact-us/
Hi – I believe I have the same problem as expresaweb – I have emailed you as well.
Thanks
The problem of BananaMan has been fixed.
Solution
Both WordPress Address (URL) and Site Address (URL) must contains “www”.